What is a prostate biopsy?
A prostate biopsy is the only medical procedure with which prostate cancer can be diagnosed conclusively.
It is performed by a urologist or radiologist when one or more anomalies have been detected in the prostate. The necessity of a biopsy is determined by a digital rectal exam, PSA test or, more recently, an MRI scan.
The exam consists of removing small samples of the organ, before analysing them under a microscope to establish the presence or absence of cancer sites, their aggressiveness and respective sizes.
Typically, ten or so samples are taken under ultrasound guidance using a fine needle approximately 1 mm in diameter and a biopsy gun. Positioned in the rectum, the ultrasound probe allows the doctor to see the prostate and guide the insertion of the needle before making the puncture.
A source of anxiety for many patients, prostate biopsies nonetheless remain a common non-painful procedure among men over the age of 50, generally performed on an outpatient basis under local anaesthetic and leading to a fast recovery.
Diagnosing prostate cancer – 2 biopsy types
A pathology affecting almost one in seven men worldwide, prostate cancer care relies, above all, on the early, accurate and reliable diagnosis of the disease.
The prostate biopsy therefore constitutes a critical stage in the patient journey. At present, there are two types of biopsy in practice.
The “blind” biopsy
The vast majority of prostate biopsies today are carried out transrectally by means of a 2D ultrasound probe. During the procedure, the doctor aims to take 12 evenly spread samples in order to maximise the chances of finding an infected site. There are two main reasons why these biopsies are referred to as “blind”:
- Conventional ultrasound techniques are not particularly effective when it comes to visualising potential cancer sites directly on the ultrasound scanner.
- The ultrasound guidance tool only allows for 2D visualisation, making it difficult to take an even spread of organ samples.
The development of multiparametric Magnetic Resonance Imaging (MRI) of the prostate has considerably improved the sensitivity and specificity of prostate cancer diagnoses – See the related studies. Given the excessive constraints associated with biopsies performed directly under MRI, an alternative has now emerged, enabling real-time integration on the ultrasound scanner of information based on MRI sequences: MRI-US fusion.